transmission problems?

[ac97gt]

if i try to shift gears quickly (like as fast as i can, and even a little bit slower) it will grind, then go into gear. its almost like my synchros are going? im going to check/change the fluid this weekend, im not sure when it was last checked/changed. is there something else i should look for too? i have only noticed it doing it from 1st to 2nd, and from 2nd to 3rd, and again, only when shifted quickly. i notice it mostly when im getting on it, because thats when you shift the fastest, but even cruising slowly through a parking lot, if i shift real fast from 1st to 2nd, it will give a nice grind, but be in gear. im sure this is bad for it, right? (i mean it cant be good for it). if its not the fluid, and its, say, the synchros, how much would that cost to fix, and how much damage would i cause by not fixing and continuing to drive like it is? i dont know alot about transmissions, but i do know that its embarassing to get on it and have gears grind

btw if i just shift normal granny speed everything is ok.

any ideas/suggestions/info? thanks guys.